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Table 5 α-Adrenergic antagonists do not inhibit the ability of catecholamines to -mediate bacterial uptake of Tf-complexed iron.

From: Blockade of catecholamine-induced growth by adrenergic and dopaminergic receptor antagonists in Escherichia coli O157:H7, Salmonella enterica and Yersinia enterocolitica

  Uptake of 55 Fe from 55 Fe-Tf (CPM)
Culture Conditions Y. enterocolitica E. coli O157:H7 S. enterica
No additions (control) 363 (14) 848 (23) 910 (33)
50 μM NE 2736 (13) 21343 (1185) 22867 (848)
50 μM NE plus 200 μM phentolamine 2375 (98) 22333 (1154) 24843 (141)
50 μM NE plus 200 μM phenoxybenzamine 2482 (93) 20205 (1058) 22106 (676)
50 μM NE plus 200 μM prazosin 3133 (37) 23189 (1185) 21109 (625)
50 μM NE plus 100 μM Fe 613 (16) 3870 (57) 6617 (246)
100 μM Epi 1759 (101) 23975 (1164) 21006 (1045)
100 μM Epi plus 200 μM phentolamine 2133 (37) 28301 (262) 21991 (827)
100 μM Epi plus 200 μM phenoxybenzamine 1987 (37) 22151 (1148) 21452 (208)
100 μM Epi plus 200 μM prazosin 1887 (104) 24682 (1059) 20403 (894)
100 μM Epi plus 100 μM Fe 238 (13) 2642 (123) 1889 (66)
  1. The table shows NE and Epi-mediated bacterial uptake of 55Fe from 55Fe-labelled transferrin in the presence of concentrations of α-adrenergic antagonists inhibitory to NE and Epi growth induction. Exponential cultures of the bacteria shown were inoculated at approximately 2 × 108 CFU/ml into triplicate 1-ml aliquots of serum-SAPI containing the compounds shown in the Table plus 2.7 × 105 cpm of 55Fe-labelled transferrin. After incubation for 6 hours bacteria were harvested, washed and measured for cellular uptake of 55Fe from 55Fe-transferrin (CPM) by scintillation counting, as described in Materials and Methods. Analysis of growth levels revealed no significant differences in growth levels between control and catecholamine/antagonist supplemented cultures. The values shown represent the means of bacterial 55Fe incorporation from triplicate 1 ml uptake assays; standard deviations are shown in brackets.